Background The FIFA 11+ was developed as a complete warm-up programme to prevent injuries in football players. Although reduced hip adduction strength is associated with groin injuries, none of the exercises included in the FIFA 11+ specifically target hip adduction strength.

Objective To investigate the effect on eccentric hip adduction strength of the FIFA 11+ warm-up programme with or without the Copenhagen Adduction exercise.

Design Randomised controlled trial.

Setting U19 elite male football teams.

Participants We recruited 45 eligible players from two teams. Per-protocol analyses were performed, with 12 players excluded due to low compliance (<67% of sessions completed).

Interventions Players were randomized into two groups; one group was asked to carry out the standard FIFA 11+ program, while another group was asked to carry out the FIFA 11+, but to replace the Nordic Hamstring exercise with the Copenhagen Adduction exercise. Both groups performed the intervention three times weekly for 8 weeks. Players completed eccentric strength and sprint testing before and after the intervention.

Main Outcome Measurements Eccentric hip adduction strength (Nm/kg).

Results Between-group analyses showed that there was a significant difference in the change in eccentric hip adduction strength of 0.32 Nm/kg (10.1%) (p=0.006) on the left side and 0.24 Nm/kg (7.2%) (p=0.046) on the right side in favour of the group performing the Copenhagen Adduction exercise. There was no within-group change in eccentric hip adduction strength in the group that did not perform the Copenhagen adduction exercise (left side: −0.03 Nm/kg (−0.8%) p=0.79, right side: −0.02 Nm/kg (−0.7%) p=0.78).

Conclusions Including the Copenhagen Adduction exercise to the FIFA 11+ programme increases eccentric hip adduction strength, while the standard FIFA 11+ programme does not. We therefore suggest adding the Copenhagen Adduction exercise to the FIFA 11+ to potentially prevent groin problems.